Fluid-handling apparatus such as dredge suction heads, and dredge conduits, require some type of screening to eliminate the entrance of large objects which will damage the pump impeller, or other components of the system. Usually, such screens consist of rectangular openings of a dimension which permits entrance of the size of a particle acceptable to the pump and conduit system and excludes others.
Debris which cannot pass through the screen will collect on the screen and be held thereagainst by the fluid flow. The screen will quickly collect such debris and become clogged if means for cleaning the screen are not available. Manual screen cleaning is time consuming and troublesome and with underwater dredging systems screen cleaning requires extensive time and expense.
A variety of devices have been utilized with dredging operations to control the size of particles entering the dredging system, and reference is made to U.S. Pat. Nos. 1,155,370; 2,260,293; 4,004,359 and 4,083,134. While the devices shown in the aforementioned patents will protect the fluid-handling system with which they are associated, screen clogging will still occur, and heretofore effective cleaning of high-capacity screens has been a serious problem.
It is an object of the invention to provide a screen for dredging systems and the like capable of handling high capacity flow, and yet effective continuous screen cleaning is provided.
A further object of the invention is to provide a rotary screen for a hydraulic system wherein ejectors sequentially clean debris from each screen opening, and the debris may be discarded or collected.
Another object of the invention is to provide a rotary screen for hydraulic systems wherein a power-driven debris ejector is used in conjunction with a rotary screen, and the ejector is rotated by the screen prime mover.
Yet another object of the invention is to provide a rotary screen which simultaneously functions as a cutterhead for underwater dredging.
A further object of the invention is to provide a rotating screen for hydraulic systems wherein the screen may be incorporated into a conduit system, and debris cleaned from the screen is collectable for removal from the hydraulic system.
In the practice of the invention a screen in the form of a drum is rotated by a hydraulic motor. The periphery of the screen is defined by a plurality of longitudinally extending slats or rails, and axially spaced rings adjacent the rails form rectangular openings at the screen periphery.
An ejector shaft is located within the screen drum parallel to the drum axis of rotation, and a plurality of ejector teeth or cones radially extend from the ejector shaft. The ejector shaft is located adjacent the screen periphery and rotates in synchronization with the screen drum whereby the teeth thereof sequentially extend through and beyond the screen periphery openings. In this manner the teeth eject debris from the openings and maintain the openings clear for fluid flow therethrough.
Preferably, a housing is located adjacent the ejector teeth having slots defined therein for receiving the teeth whereby movement of the teeth through the slots strips debris from the teeth. When the screen is used in a conduit system a debris receiving receptacle is preferably located adjacent the ejector for receiving the foreign matter removed from the screen.
Rotation of the ejector shaft is by means of a pinion gear engaging a ring gear concentrically attached to the screen drum. Thus, synchronization of rotation between the drum and ejector shaft is assured, and only the single motor rotating the screen drum is required to rotate both the screen and the ejector shaft.